User experience
Slow responses make autocomplete and result pages less useful, especially on mobile.
Glossary
Query Latency
Query Latency is the time between sending a search question and receiving a useful search layer answer.
Not just averages
Percentiles and slow outliers show problems that an average can hide.
Segmenting
Measure where relevant per endpoint, region, device, store and tax level.
Operational context
Combine latency with availability, errors and index freshness to properly explain performance.